Whole body plethysmography measurement of respiratory function of mice in vivo (1178.9)

Abstract

Applied physiology research commonly incorporates mouse models, but in vivo physiologic measures in conscious rodents can be difficult to collect. Since recommendations for standardized whole body plethysmography (WBP) use do not currently exist, the current study employed WBP to quantify pulmonary function in conscious mice. Two month old Male C57BL6 and MDX mice (n=8/group) were housed on a reverse light cycle and examined on consecutive days using a calibrated WBP (Fine Pointe unrestrained WBP, Buxco Electronics). Multiple measurements such as time of day (8 am, 12 pm, 3 pm, 6:30 pm), environment lighting influence, and day‐to‐day reproducibility as well as chamber habituation time required for stable data collection plateau were recorded. Fine Pointe software was used to determine respiratory rate, tidal volume, minute ventilation, peak inspiratory flow, peak expiratory flow, inspiratory time, expiratory time, and relaxation time between breaths. Statistical observance of respiratory chamber habituation occurred between 5‐10 mins from the start of collection for all variables measured. Reverse light cycle housed mice exhibited significant time of day pulmonary function differences, performing more forceful and less frequent breaths during the middle of the day (12 pm & 3 pm). Significant differences were observed for WBP performed in lighted vs. darkened conditions, with the latter eliciting more forceful breathing. Day‐to‐day reproducibility was significant (p<0.05) with a range of from r2=0.58 to r2=0.62 for measures collected. Findings indicate good reproducibility of WBP is possible provided investigators collect data after at least a 10 minute habituation period and standardize time of day and room lighting used for data collection. This work supported by the Duchenne Alliance and its member foundations.Grant Funding Source: Duchenne Alliance and member foundations